Factors related to rice taste and nutritional quality in the “Gongtian” of Huayangxi Village, Huaihua, Hunan

  Objectives  The rice produced in the Gongtian in Huayangxi Village of Huaihua in Hunan Province is specified product for the royal monarch in the history. Thus, we explored the environmental factors influencing rice quality from Gongtian.

  Methods  Field experiments were conducted in the Gongtian and nearby non-Gongtian fields in Huayangxi Village, Huaihua City in Hunan, using three rice cultivars (Hezhongxiang, Suiwanxiang, and Nongxiang 25) as test materials, under mono-cropping system. After rice harvest, the soil samples of 0−20 cm plough layer were sampled for determination of organic carbon, total and available nutrient contents, the irrigation water samples were collected for analysis of 22 mineral element contents, and rice samples were collected for the measurement of taste quality (appearance, viscosity, hardness, balance, taste value) and nutritional quality (protein, fat, starch).

  Results  Compared with non-Gongtian, Gongtian had significantly higher organic matter, total N and P, available K and P contents, higher microbial biomass carbon and microbial biomass nitrogen, microbial biomass phosphorus content, and higher total Fe and Al contents. The rice from Gongtian accumulated more Zn, Ru and Sr and higher relative fat content in grain than that from non-Gongtian. Gongtian rice also had the higher grain taste quality (viscosity, appearance, and taste value) than that from non-Gongtian. The results of redundancy analysis showed that soil total nutrients, available nutrients and microbial biomass accounted for 59% of variation in rice taste and nutritional quality. The structural equation model showed that the content of 22 elements in soil was positively correlated with that of rice. The content of elements in irrigation water was low, and had little effect on the taste and nutritional quality of rice.

  Conclusions  Due to long-term manuring, the Gongtian had significantly high soil fertility (total and available nutrients, microbial biomass and soil element content), and thus significantly higher rice yield than the rice in nearby common fields. Cultivar is a stable and decisive factor for the rice taste, which is less affected by soil properties. Under the current fertilization method, rice has higher fat contents and lower protein contents, which strengthen the rice taste as well.